A mass flow controller (MFC) is a device to measure and control the flow of liquids and gases. In general, an MFC includes an inlet port, an outlet port, a mass flow sensor and a proportional control valve that is adjusted to achieve a desired mass flow.
Semiconductor fabrication processes, such as atomic layer deposition (ALD) processes, can involve the delivery of several different gases and gas mixtures in various quantities over several processing steps. Generally, gases are stored in tanks at a processing facility, and gas metering systems are used to deliver metered quantities of gases from the tanks to processing tools, such as chemical vapor deposition reactors, vacuum sputtering machines, plasma etchers, etc. Typically, components such as valves, pressure regulators, MFCs, mass flow ratio control systems, etc. are included in the gas metering system or in a flow path from the gas metering system to a processing tool.
Pulse gas delivery devices have been developed to deliver a pulsed mass flow of a gas to semiconductor process tools.